AS PER GTU SYLLABUS ENVIRONMENTAL ENGINEERING (5TH SEM)

1. House
Drainage

2.  House drainage :- The principles and procedure to be
followed while constructing and laying sewer lines in private
buildings are referred as ‘house drainage ’.
 Aims :-
1.To maintain healthy condition in the building .
2.To dispose off waste water as early and quickly as possible .
3.To avoid the entry of foul gases from the sewer or the septic
tank .
4.To facilitate quick removal of foul matter.
5.To collect and remove waste matters systematically .

3.  Principles of housedrainage:-
1.It advisable to lay the sewers by the side of the building
rather than below the building .
2.All the drain should be laid straight between inspection
chambers, avoiding sharp bends and junction as far as
possible .
3.The house drain should be connected to the public sewer
only when the public sewer is deeper than the house drain in
order to avoid reverse flow from the public sewer to the house
drain .
4.House drainage should contain enough traps at suitable

4. 5. The joints of sewer should be properly tested before putting the
drainage line to use .
6. Lateral sewer should be laid at proper gradient so that they can
develop self cleansing velocity.
7. The size of drain should be sufficient , so that they do not
overflow at the time of maximum discharge .
8. The layout of house drainage should permit easy cleaning and
removal of obstructions .
9. The entire system should be properly ventilated from the starting
point to the final point of disposal .
10. All the materials and fittings of the drainage system should be
hard , strong and resistant to erosion action . They should be
non-absorbent type .

5. Definition:-
1.Sewage :- The term sewage is to indicate the liquid wastes
from the community . It includes discharge from bathrooms ,
kitchen , washing places , wash basins , latrines , urinals ,
industrial wastes and storm water .
2.Sullage :- Sullage is used to indicate the waste waters from
bathrooms , kitchens , washing places , wash basins , etc.
3.Sewerage :- The entire science of collecting and carrying
sewage by water carriage system through sewer , is known as
sewerage .

6. 4. Sewer :- An underground pipe or conduit which carries
sewage is called sewer .
5. Vent pipe :- The pipe installed for the purpose of ventilation
is known as vent pipe .
6. Plumbing system :-Plumbing system is the entire system of
piping's , fixtures , pipelines , etc . For providing water
supply or drainage to the building .
7. Sewerage system :- A system of sewers of different types
and sizes in a town collecting wastewater from the town
and carrying it to the waste water treatment plant .

7. 8. Rainwater pipe :- It is a pipe which carries only the
rainwater .
9. Trap :- The which is connected at the end of the soil pipe
or waste pipe to stop the entry of foul gases inside the
building is known as trap .
10. Water seal :- The vertical distance between the crown and
the dip of the trap is known as water seal . This portion
always remains full of water . Generally , the water seal
varies from 75 mm to 100 mm .

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1. Soil pipe : it is the pipe carrying sewage from urinals , water closet
, etc.
2. Waste pipe : it is pipe carrying from bathrooms , kitchen , sinks
etc. It does not carry human excreta.
3. Vent pipe: the pipe installed for the purpose of ventilation of the
system is known as vent pipe .
4. Rain water: it is a pipe which carries only the rain water .
5. Antisiphonage pipe : a pipe which is installed in the house
drainage to preserve the water seal of the traps is known as
antisiphonage pipe .
6. Ventilating pipe : the ventilating pipe enables the foul gases of
 PIPES

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 Soil pipe: 100mm
 Waste pipe: horizontal: 30-50mm
 Waste pipe: vertical : 75mm
 Rainwater pipe : 75mm
 Vent pipe: 50mm
 Connecting soil pipe: 50mm
 Connecting waste pipe: 40mm
SIZES OF PIPES

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PIPES
Material Application Jointing
Cast iron 50 mm and above vent and discharge
stacks
Lead caulking with molten or fibrous
lead; cold compound caulking
Galvanized steel Waste pipe Screwed
Copper Waste pipes and traps Compression, capillary, silver solder,
bronze weld or push-fit rings seal
Lead Waste pipes and discharge stacks Soldered or lead welded
ABS (acrylonitrile
butadiene styrene)
Up to 50 mm waste and vent pipes Solvent cement and push-fit ring seal
High-density
polyethylene
Up to 50 mm waste and ventilating
pipes and traps
Push-fit ring seal and compression
fittings
Polypropylene Up to 50 mm waste and ventilating
pipes and traps
Push-fit ring seal and compression
couplings
Modified PVC Up to 50 mm waste and vent pipes Solvent cement and push-fit ring seal
Unplasticized PVC Over 50 mm soil and vent stacks; vent
pipes under 50 mm
Solvent cement and push-fit ring seal
Pitch fibre Over 50 mm discharge and vent stacks Driven taper or polypropylene fitting
with a push-fit ring seal

11. Traps :-
The device which is connected at the end of soil
pipe or waste pipe to stop the entry of foul gases inside the
building is known as trap . It is a bent pipe in the shape of ‘u’
which always remain full of water. The depth of water seal is
the vertical distance between the crown and dip of a trap. The
depth of water seal represents its strength or effectiveness.
Greater the depth of water seal more effective is the trap. The
depth of water seal varies from 25mm to 75mm.

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Causes of failure of waterseal :-
1.Faulty joints
2.Crack in the bottom of seal
3.Creation of partial vacuum in the sewer fittings
4.Increase in the pressure of sewer gases
5.Non-use for a prolonged period
Prevention:-
1.Connecting the portion between the soil pipe and trap
by a vent pipe .
2.Use of anti- siphonage pipe in the building

14. Requirement of a good trap :-
1.It should possess a adequate water seal at all times .
2.It should be not absorbent material .
3.The internal and external surface should have smooth finish
so that dirt , etc. Does not stick to it .
4.It should be free from any inside projection , angles ,
contractions, so that flow is not obstructed.
5.It should be self cleansing .
6.It should be simple in construction , cheap and readily
available .
7.It should be provided with suitable access for cleaning.

15. Classification of traps :-
A.Classification according to shape :
1.P – trap
2.Q – trap
3.S – trap

16. B. Classification based on use :
1. Floor trap or nahni trap :
A floor trap a commonly known as a nahni trap is
used to collect wash water from floor, kitchen and bathrooms .
It forms the starting point of waste water flow. It is generally
made of cast iron .

17. 2. Gully trap :
These are special type of traps which disconnect
sullage drain from the main drainage system . A well
designed gully trap serve two or three connections from the
nahni trap .

18. 3. Intercepting trap :
The intercepting trap is also known as disconnecting
trap or interceptor . It is provided at the junction of the house
drain with the public sewer or septic tank . It is thus provided
in the last man hole of the house drainage system.

19.
These trap is to remove oily waste from wastewater. It is
used in large hotels, restaurants or industries where large
quantities of oily waste are expected to enter. It is generally made
up from Masonry or cast iron and bent or tee pipe at the outlet.
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4. Grease trap:

20. Sanitaryfittings :-
1.Wash basin
2.Sinks
3.Bath tub
4.Water closet
5. urinals
6.Flushing cistern

21. Many wash basin designs are available, ranging from surgeon’s basin
to small hand basin. They can be obtained to fit into a corner of the
room and may be supported on brackets, a pedestal or by a ‘built in’
corbel.
A wash basin is usually made of pottery or white glazed earth ware or
enameled iron, etc. Sometimes, they are also made of pressed steel
or plastic. There are two types of wash basins - the flat back and the
angle back.
An ordinary wash basin is mounted on brackets fixed on wall. While a
pedestal type basin is mounted on pedestal rising from wall. They are
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WASHBASIN

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Standard sizes for flat back wash basins are
630 x 450 mm
550 x 400 mm
450 x 300 mm
Standard sizes for angle back wash basins are
600 x 480 mm
400 x 400 mm
 It has oval shaped bowl. with overflow slot at the top, The
waste pipe with a metallic strainer is provided at the bottom of
the bowl.

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24. SINK
Sinks of all types are in wide use in a multitude of different
applications. Such as Surgeon’s scrub sinks, service sinks, lavatories
sinks, bar sinks, kitchen sink are just a few of the more common ones
used in plumbing systems.
 Sinks can be made of porcelain, stainless steel, plastic, fiberglass or
any other nonporous material.
The sink has an outlet usually of about 40 mm diameter. The outlet
pipe discharges water over a floor trap or nahni trap. The mouth of outlet
pipe is provided with grating of bras or nickel so that the entry of coarse
solid substances is prevented. 24

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Common sizes of kitchen sinks:
600 x 400 x 150 mm
600 x 450 x 250 mm
750 x 450 x 250 mm
Common sizes for laboratory sinks:
400 x 250 x 150 mm
450 x 300 x 150 mm
600 x 400 x 200 mm

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BATHTUBS
 A sanitary appliance in which the human body can beA sanitary appliance in which the human body can be
immersed and cleansed.immersed and cleansed.
 Bath tubs are available in enameled cast iron, pressed steel orBath tubs are available in enameled cast iron, pressed steel or
in various types of plastics and acrylics.in various types of plastics and acrylics.
 Bath tub should be fixed as low as possible to assist getting inBath tub should be fixed as low as possible to assist getting in
and out. The water supply may be pillar tabs or by a specialand out. The water supply may be pillar tabs or by a special
fitting incorporating a diverter and a shower.fitting incorporating a diverter and a shower.

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 For domestic installations, the taps and supply pipes are 19For domestic installations, the taps and supply pipes are 19
mm internal diameter, but for institutions these aremm internal diameter, but for institutions these are
sometimes enlarge to 25 mm, to increase the speed ofsometimes enlarge to 25 mm, to increase the speed of
filling.filling.
 The usual dimensions of both tub are:
length : 1.7 to 1.85 m
width : 0.70 to 0.75 m
depth : 0.6 m

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WATERCLOSET
 A water closet is a sanitary fitting which is designed to receive
human excreta directly and convey to the septic tank or
underground sewer through a trap.
 It is usually connected to a flushing cistern to flush the closet
and discharge the human excrete to the soil pipe.
 This is the most common type of plumbing appliance and also
known as a toilet. Water closet are usually subdivided according
to where they are mounted (floor mounted and wall
mounted ) and how they are flushed (tank type and flush valve

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 The most widely used pattern is the “wash-down”, in which the
contents of the pan are removed by gravity water flush. The pan
shape has been developed from the earlier long and short hopper
types, to provide the minimum of fouling area. They are designed
to maintain a 50 mm minimum water seal.
 The outlet may be obtained left or right hand and also ‘P’ or ‘S’
as shown; it may be flushed from a high or low level flushing
cistern. The high-level cistern provides a more effective flush
compare to low level cistern.

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The water closets are of three type :
1) Indian type
2) European type
3) Anglo- Indian type

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URINAL
 They are designed to accept and dispose of liquid humanThey are designed to accept and dispose of liquid human
wastes only. The types of urinal are ceramic slab , stall typewastes only. The types of urinal are ceramic slab , stall type
and bowl type.and bowl type. Stall urinals has more than one units, with a c/c
spacing of 0.6 to 0.7 m. Made up of stoneware, slate and
cement. Discharging of waste into soil pipe through floor trap.
 Automatic flushing cisterns are generally provided in stall type
which operates at regular interval of 10 to 15 mins.
 The slab type is cheaper than the stall type , but it does notThe slab type is cheaper than the stall type , but it does not
provide the same degree of privacy.provide the same degree of privacy.

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 The installation of ceramic bowl-type urinal, which haveThe installation of ceramic bowl-type urinal, which have
less fouling area then the slab and stall urinals.less fouling area then the slab and stall urinals.
 Standard size of these urinals as follows:
Flat back pattern 430*260*350 mm
Angle back pattern 340*430*265 mm

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SLAB URINAL STALL URINALSTALL URINAL

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FLUSHINGCISTERN
Function :
Used to flush away the contents of soil fitting to the drain.
It is installed to flush the water closet and urinal.
Specification:
Fixed 2m and 0.6 m above floor level.
Capacity of the cistern from 5 to 15 liters (popular : 9 liter)
For Indian w/c, flushing cistern are made from cast iron and fixed
at a height of about 1.75 m above the top of the closest pan.

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PISTON FLUSHING CISTERN
•The piston type flushing cistern,
operates as follows:
•When the lever is depressed
sharply, the piston is lifted, which
displaces water over the siphon.
•Water discharging down the flush
pipe takes some air with it and creates
a partial vacuum in the siphon.
•The greater air pressure acting
upon the water in the cistern forces
water through the siphon until air is
admitted under the piston, which
breaks the siphon action.

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AUTOMATIC FLUSHING CISTERN
•Automatic flushing cistern designed
to discharge its contents of water at
regular intervals into a urinal.
•The rate at which the water will
flush depends upon the rate at which
the water is fed into the cistern and for
a single installation this should not
exceed ten liters per hour. These flush
water automatically once in 10 – 15
minutes.
•To prevent wastage of water from
these cistern, at times when the cistern
is not used such as at weekends, an
Auto m atic Flo w Cut O ff De vice should
be fitted.

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• The bell-type flushing cistern
is rather noisy but may be
used in factories and schools.
• The cistern is operated by the
chain being pulled down which
also lifts the bell.
• When the chain is released
the bell falls thus displacing
water under the bell down the
stand pipe.
• Siphonic action is then created
which empties the cistern.
BELL-TYPE FLUSHING CISTERN

41.  Systemof plumbing:-
There are four principal system of plumbing for drainage of
building :
1.Single stack system
2.One pipe system
3.Partially ventilated single stack system
4.Two pipe system

42. 1. Single stacksystem :-
This is the simplest system, in which the waste
matter from bathrooms , kitchen , sinks etc. As well as foul
matter from the WC and urinals are discharged in one
single pipe , called the soil pipe and waste pipe . This pipe
terminates as the vent pipe at its top , and no separate
vent pipe is provided .

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• The single stack system Reduces
the cost of soil and waste systems.
• Branch vent pipes are not
required
• To prevent loss of trap water
seals:-
• The trap water seals on the waste
traps must be 76 mm deep.
• The slopes of the branch pipes
are: sink and bath, 18 to 19 mm/m;
basin 20-120 mm/m; WC 18 mm/m
(min.).
• Vertical stack at 200 mm below
the centre of the WC branch

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2. ONE PIPE SYSTEM
• In this system a separate vent pipe
is provided and the traps of all
water closet , basins, etc, Are
commonly ventilated .
• In the system all soil and waste
water discharge into one common
pipe and all branch ventilating pipes
into one main ventilating pipe.
• This system largely replaces the
two pipe system and lent itself very
well to use in multi storey
developments.
• It is far more economical than the
two pipe system.

45. 3. Partially ventilated single stacksystem :-
This is a modified form of the single stack system
and one pipe system . In this system the waste from WC ,
basins , sinks , etc , is discharged in to one common soil
and waste pipe .

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• Close grouping of the sanitary
appliances  install the branch waste
and soil pipes without the need for
individual branch ventilating pipes.
• To prevent the loss of trap water seals
 WC branch pipe min. 100 mm bore
and the angle θ = 90.5° to 95°.
• To prevent the loss of trap water seals
 basin main waste pipe min. 50 mm
bore and the angle θ = 91° to 92.5°.
• Five basins or more / length of the
main waste pipe exceeds 4.5 m  a
25 mm bore vent pipe connected to
main waste pipe at a point between
the two basins farthest from the stack.

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4. TWO PIPE SYSTEM
• In this system separate soil pipe and
waste pipe is provided. The discharged
from WC is connected to soil pipe while
the discharge from bath , sinks ,
lavatory basins etc. Are connected to
waste pipe
• The waste stack received the discharge
ablutionary fitments and conveyed this
to the ground level where it was
delivered above the water seal in a
trapped gully connected to the drainage
system.
• The soil stack receives the discharge
from soil appliances and delivered it
direct to the underground drainage
system. The waste and soil water did
not combine until they reached the

48. Testingof drains andpipes :-
After laying a house drains and fitting the pipes , their
water tightness should be ascertained by applying various test . The
drains are usually tested in section between successive chamber
and vertical pipe are tested in groups having one common inspection
chamber .
The following test are usually conducted :
1.Air test
2. coloured water test
3. hydraulic test
4.Smell test
5. smoke test

49.  Maintenanceof housedrainagesystem:-
1. Entry of undesirable elements : Care should be taken to
see that undesirable substances like grit , sand , decayed
fruits , vegetables , pieces of clothes leaves , etc . Do not
enter the system .
2. Flushing :- It is advisable to flush the system once or twice
a day in order to maintain it in working condition .
3. Inspection :- Various unit of house drainage system should
be inspected at regular intervals and the obstruction , if any
, should be removed .
4. Quality of material :- Good quality material should be used

50. Precautioninplumbingwork:-
1.For all pipes , fitting , etc. Standard material should be used
. Sub –standard material may caused leakage in pipe and
fitting .
2.All the joints should be made water tight by wrapping jute
thread and white lead paint in the threads , while screwing .
3.Over screwing of pipes , fittings , elbow , tee , sockets ,
cross etc . Should not be done to avoid cracks .
4.The pipes should be cut at right angle to the axis of the
pipe .

51. Thank you